1. Field of the Invention
The present invention relates to a communication system, a communication method and a radio communication apparatus.
2. Description of the Related Art
In recent years, a user device such as a radio communication apparatus is capable of executing an application via a network. There are following two concrete execution methods, for example.    (1) An execution method based on a concept such as an “X terminal” and a “thin client” (See Japanese Patent Application Laid-Open No. 2003-141064, for example).
An application server is provided on a network and executes a program (application) according to user's operation on a radio communication apparatus.    (2) An execution method based on a concept such as an “agent.”
An application server is provided on a network, and a radio communication apparatus downloads a program from the application server via the network and executes the program.
In the method (1), when the distance between the radio communication apparatus and application server increases, a delay may increase or the communication speed may be reduced due to a bottleneck in a communication path. In addition, it is difficult to find a more preferable wireless network than a currently used wireless network. On the other hand, in the method (2), the radio communication apparatus may have an insufficient signal processing speed or memory capacity for an application.
There are plural base stations on the network and the radio communication apparatus can communicate with the application server by radio communication via one of the base stations. Further, when the distance from the base station increases and the radio communication quality is deteriorated, the radio communication apparatus is handed over to another base station according to need.